Irritable Bowel Syndrome (IBS)

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What is IBS?

IBS Singapore

IBS (irritable bowel syndrome) - not to be confused with IBD - is a common chronic disorder affecting the large intestine, with no known cause. It is a functional disorder manifesting with symptoms such as abdominal cramps/pain, bloating, constipation and/or diarrhoea, but the symptoms may vary depending on the subtype of IBS and its severity.

It is important to note that IBS is a medical diagnosis and not an all-encompassing term your doctor uses when they cannot determine the exact cause of your bowel issues. However, because the condition often has no definitive cause, it also does not have a definitive cure. 

Treatment largely revolves around minimising and managing IBS symptoms. Most people do not develop severe IBS and are able to cope by managing their diet, lifestyles or stress levels. More severe IBS may be treated with certain medications. If you do experience IBS symptoms, it is important to get it checked as it may be suggestive of more serious conditions. 

What are the symptoms of IBS?

The signs and symptoms of IBS are generally chronic. These vary from person to person, and one’s pattern of symptoms may even change over time. The most common symptoms are:

  • Abdominal cramps, pain or discomfort, often associated with bowel movements
  • Increased frequency of bowel movements or passing gas
  • Altered appearance of stools (eg. constipation, diarrhoea, mixed, mucoid)
  • Bloating
  • Lethargy

The list of symptoms is non-exhaustive, and a person living with IBS may have a few or all of these, depending on the severity. The diagnosis of IBS should be made by a doctor, and we’ll explain how it’s diagnosed further below.

Can dairy cause IBS?

Dairy may cause IBS symptoms, especially if the dairy product is high in fat. Switching to low-fat or non-fat dairy products may alleviate your symptoms.

How do I tell the difference between IBS and other diseases?

There are many other diseases that can affect your gastrointestinal tract just like IBS and cause similar symptoms, but the underlying cause and eventual treatment of these diseases vary.

How is IBS diagnosed?

One thing to note is that IBS is a diagnosis of exclusion. This means that your doctor will rule out other possible conditions causing these symptoms before coming to this diagnosis. 

The Rome IV criteria is used to diagnose IBS. The below criteria are directly taken from the Rome Foundation’s website:

  • Recurrent abdominal pain on average at least 1 day/week in the last 3 months, is associated with two or more of the following criteria:
    • Related to defecation
    • Associated with a change in frequency of stool
    • Associated with a change in form (appearance) of stool
  • Criteria fulfilled for the last 3 months with symptom onset at least 6 months prior to diagnosis

Tests such as blood investigations, stool tests and hydrogen breath tests are often not required to diagnose IBS, but may be used to assess your baseline health and to rule out other more serious conditions. 

A colonoscopy may be done as a routine age-based screening for colorectal cancer, as well as to exclude other diseases of the intestines that may cause constipation/diarrhoea.

Three subtypes of IBS

IBS is often grouped into 3 broad subtypes to guide treatment, and they are based on the predominant type of stool on days with at least 1 abnormal bowel movement:

  1. IBS-C (IBS with constipation)
  2. IBS-D (IBS with diarrhoea)
  3. IBS mixed (IBS-M)

If your symptoms do not fall into the 3 subtypes, it may fall under the umbrella of IBS-U (IBS Unspecified).

IBS with constipation (IBS-C)

Most of your poop is hard and lumpy.

IBS-C is diagnosed if constipation is the predominant type of stool on ≥25% of the days when you have at least 1 abnormal bowel movement, and ≤25% of the days are characterised by diarrhoea. The appearance of constipation is often lumpy, hard pellets or lumpy sausage-shaped stools.

This subtype of IBS means one often experiences constipation, less frequent bowel movements, abdominal pain and bloating. However, constipation leads to straining when defecating and you may notice some blood when wiping afterwards.

IBS with diarrhoea (IBS-D)

Most of your poop is loose and watery.

IBS-D is the opposite of IBS-C: it is diagnosed when diarrhoea is the predominant type of stool on ≥25% of the days when you have at least 1 abnormal bowel movement, and ≤25% of the days are characterised by constipation.

This subtype is often associated with increased frequency of bowel movements, cramp-like abdominal pain (related to defecation), bloating and gas.

IBS-mixed (IBS-M)

Most of your poop is hard and lump and loose and watery on the same day. 

Last but not least, IBS-M is IBS with mixed bowel habits, referring to alternating constipation and diarrhoea.

In this form of IBS, out of all the days when you have at least 1 abnormal bowel movement, constipation is the predominant type of stool on ≥25% of the days and diarrhoea predominates on ≥25% of the other days.

Can IBS be cured and how is it treated?

IBS does not have a definitive cure at the moment, hence the treatment of IBS is centred around relieving symptoms and minimising the impact of IBS on patients’ lives.

Patients with milder symptoms can often cope by managing their diet & lifestyle. Certain types of food can aggravate or increase the frequency of bowel movements and should be avoided. 

Leading a healthy lifestyle, in general, helps as well, and this includes managing stress levels, having adequate hydration & a high-fibre diet and exercising regularly.

For those with more severe symptoms or if IBS is significantly hampering their daily life, the doctor may prescribe medication to aid with the symptoms. Various medications may partially alleviate abdominal cramps and reduce the frequency of diarrhoea, as well as laxatives to relieve constipation. If stress is a significant trigger for IBS, psychological therapy in the form of counselling may be of use as well.

Low-FODMAP diet

How about the Low-FODMAP diet?

FODMAP refers to fermentable oligosaccharides, disaccharides, monosaccharides and polyols, which are short-chain carbohydrates (sugars) that are often more difficult for the small intestine to absorb. 

The Low-FODMAP diet is a temporary restrictive diet that allows the patient to discern what foods may be causing IBS symptoms. This involves avoiding FODMAP foods and slowly reintroducing them into your diet to see how your digestive system responds. 

By understanding exactly what types of food are causing your IBS symptoms, you’d be able to effectively manage your IBS while enjoying everything else worry-free.


In Dr Benjamin Yip’s personal opinion, IBS symptoms are varied and can occur in many other digestive diseases as well. It is important for you to be assessed by a Gastroenterologist to make sure you do not have other more serious digestive conditions.

While it is a lifelong condition with no definitive cure, it can be well-controlled if one is compliant with your gastroenterologist’s treatment plan to minimise IBS’ impact on your daily life.


  1. Blanton, Nicole. “The gut-brain connection: How psychotherapy treats irritable bowel syndrome.” Baylor College of Medicine Blog Network -, 10 January 2019, Accessed 11 May 2022. 
  2. “Ease IBS Symptoms With a High-Fiber or Low-Fiber Diet.” UPMC HealthBeat, 26 March 2016, Accessed 11 May 2022. 
  3. Khatri, Minesh. “Diverticulitis Treatment: How To Treat It & Recovery Time.” WebMD, 21 June 2021, Accessed 11 May 2022.
  4. “Colorectal Cancer in Inflammatory Bowel Disease.” PubMed, Accessed 11 May 2022  
  5. “Rome IV Criteria - Rome Foundation.” The Rome Foundation, Accessed 11 May 2022. 

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Dr Benjamin Yip

Consultant Gastroenterologist
MBBS (Singapore), MRCP (UK), MCI (NUS), FRCP (Edin), FASGE (USA), FAMS (Gastroenterology)

Dr Benjamin Yip is a Consultant Gastroenterologist and the Medical Director of the Alpha Digestive & Liver Centre.

Dr Yip believes that gastrointestinal health is hugely interconnected to our whole-body health and sees patients with General Medical, as well as Gastroenterology and Hepatology problems.

His expertise lies in Advanced Endoscopy, including complex endoscopic procedures such as ERCP, EUS, single balloon enteroscopy, Spyglass cholangioscopy and enteral dilation/stenting.

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